Hazards, disasters and vulnerability

Detail

1. Change in nature: the starting point

• Change is always happening in nature. NCERT sorts it in two ways:

Basis	Type	Examples
Speed	Gradual (slow, over thousands to millions of years)	landform evolution, e.g. a river slowly cutting a valley
Speed	Sudden (in seconds to days)	earthquakes, tsunamis, volcanic eruptions
Spread	Local (affects a small area)	hailstorm, tornado, dust storm
Spread	Global (affects the whole Earth)	global warming, ozone depletion

• Value-neutral vs value-loaded:
• For nature, change is value-neutral. It is neither good nor bad. It is just a process.

• For people, change is value-loaded. It is "good" if it helps them and a "disaster" if it harms their lives and property.

• So a disaster is judged from the human point of view. A flood in an empty valley is a natural event. The same flood in a crowded town is a disaster.

2. Disaster: definition

• Disaster (NCERT): an undesirable occurrence:
• caused by forces that are largely outside human control;
• that strikes quickly with little or no warning;
• that causes or threatens serious disruption of life and property, including death and injury to many people;

• that needs efforts beyond the normal statutory emergency services, such as police, fire brigades and hospitals working on a normal day.

• Simple test: if the affected community cannot cope using only its own resources, the event is a disaster.

• A disaster can be natural (cyclone, earthquake) or human-made (gas leak, war).
• Each disaster is unique. Its effects depend on the local socio-environmental setting, meaning the local land, climate, economy, housing and social groups. The same cyclone does very different damage in a well-prepared coastal district and a poor one.

3. Natural hazard vs disaster

• Natural hazard: an element of the natural environment that could harm people or property. It is a possible danger, not yet a loss.
• Ocean currents: strong currents can sink boats and drown swimmers.
• Steep, unstable slopes of the Himalayas: young, weak rocks and heavy rain make landslides likely, as in Uttarakhand and Himachal Pradesh.

• Extreme climates: very harsh desert climates (Thar, Rajasthan) and glacial climates (Ladakh, high Himalayas).

• How a hazard becomes a disaster:

• A hazard exists (e.g. an active fault line under the Himalayas).
• People and buildings are placed in its path (towns, dams, roads).

• The hazard strikes, and the damage is large-scale. Only then is it a disaster.

• Key difference:

Feature	Natural hazard	Disaster
Nature	possible threat	actual event with losses
Damage	none yet	large-scale death, damage and disruption
Coping	not needed yet	needs help from outside the community
Example	steep Himalayan slope	a landslide that buries a village

• Sequence to remember: hazard → (if it meets vulnerable people) → disaster.

4. Vulnerability: why losses keep rising

• Vulnerability: how likely people, buildings, economies and the environment are to be harmed by a hazard. It is high where houses are weak, people are poor, and warning and rescue systems are poor.
• Technology raises vulnerability (NCERT):
• Technology (embankments, pumps, tall buildings, reclaimed land) gives people confidence to settle in risky places.
• So people crowd into hazard-prone areas such as floodplains (Ganga–Brahmaputra plains) and coastal megacities such as Mumbai (west coast, Maharashtra) and Chennai (east coast, Tamil Nadu).

• More people and property in danger zones → vulnerability keeps rising, even if the hazard itself has not grown.

• Why India is extra vulnerable (NCERT, Class 11 exercise):

• Large size: many climate zones and landforms, so many types of hazard.
• Colonial past: weak infrastructure and poverty left behind.
• Social discrimination: poor people, Dalits, tribal people and women often live in the most unsafe places and get help last.
• Large population: high density means many people are hit by each event.

5. Risk, exposure, capacity and resilience (beyond NCERT)

• Disaster risk (UNDRR): the possible loss of life, injury, or destroyed or damaged assets in a system, society or community over a given period of time. It is worked out by probability, as a function of hazard, exposure, vulnerability and capacity [3].
• Exposure (UNDRR): people, infrastructure, housing, production capacity and other human assets located in hazard-prone areas [3].
• These definitions come from the Sendai Framework Terminology on Disaster Risk Reduction, adopted by the UN General Assembly on 2 February 2017 [3].
• Working formula (for answers):

Risk = Hazard × Exposure × Vulnerability ÷ Capacity

• Hazard: how strong and how frequent the threat is.
• Exposure: how many people and assets are in its path.
• Vulnerability: how easily they are harmed.

• Capacity (or coping capacity): the skills, money, institutions and plans a community can use to manage the hazard. More capacity means less risk.

• Resilience: the ability of a community to absorb a shock, adapt and recover quickly. It brings normal life back sooner.

• Policy lesson: we cannot stop a cyclone (hazard). We can cut risk by:
• moving people out of danger zones (less exposure);
• building strong houses (less vulnerability);

• setting up warnings and shelters (more capacity).

• Global frameworks that moved from "relief after disaster" to "reducing risk before disaster":

• Yokohama Strategy (1994)
• Hyogo Framework for Action (2005-2015)
• Sendai Framework for Disaster Risk Reduction (2015-2030)

6. India's hazard profile

• NCERT: about two-thirds of India's area and people are vulnerable to disasters.
• National vulnerability profile (NIDM, 2025):

Hazard	Share of India exposed
Earthquakes (moderate to very high intensity)	about 58.6% of landmass [2] (often rounded to 59%)
Floods and river erosion	over 40 million ha, about 12% of land [2]
Cyclones and tsunamis	about 5,700 km of the 7,516 km coastline [2]
Drought	68% of cultivable area [2]
Landslides and avalanches	hilly areas, mainly the Himalayas and Western Ghats [2]

• Spatial pattern:
• Earthquakes: the Himalayan belt (J&K to Arunachal Pradesh), the North-East, Kachchh (Gujarat) and the Andaman and Nicobar Islands.
• Floods: the Ganga–Brahmaputra plains (Assam, Bihar, Uttar Pradesh, West Bengal).
• Cyclones: the east coast is hit more often than the west, especially Odisha, Andhra Pradesh, Tamil Nadu and West Bengal.
• Drought: the dry west (Rajasthan, Gujarat) and the rain-shadow Deccan (interior Maharashtra, Karnataka, Telangana).

7. Human-made disasters

• Human-made disasters are caused by human action or carelessness. NCERT gives two kinds:

Type	Meaning	Examples
Direct	human action itself causes the disaster	Bhopal gas tragedy (1984), Chernobyl nuclear accident (Ukraine, then USSR, 1986), wars, release of CFCs (chlorofluorocarbons, which harm the ozone layer), greenhouse gases, pollution
Indirect	human action makes a natural hazard worse	landslides and floods caused by deforestation, unscientific land use and building in fragile areas such as Himalayan slopes and river beds

• Indirect chain:
• Forests are cut on hill slopes.
• Roots no longer hold the soil, and rain runs off fast.
• Result: more landslides in the hills and more floods downstream.

8. Bhopal gas tragedy (1984)

• Where: Bhopal, capital of Madhya Pradesh, at the Union Carbide India Ltd pesticide plant.
• When: night of 2-3 December 1984.
• What: about 40 tonnes of methyl isocyanate (MIC), a highly poisonous gas used to make pesticides, leaked into the air.
• Effects: thousands killed and hundreds of thousands injured. Many still live with lung, eye and nerve damage, and children were born with defects.
• Policy result:
• Environment (Protection) Act, 1986: an "umbrella" law that lets the Centre protect the environment and control hazardous substances.
• Public Liability Insurance Act, 1991: firms that handle hazardous substances must buy insurance so that victims get quick relief without proving negligence.

• (See the polity and environment notes.)

• Lesson: this is a technological (industrial) disaster. It shows how poor slums packed next to a factory raised exposure and vulnerability.

9. Classification of natural disasters (NCERT Class 11, Table 6.1)

Class	Disasters
Atmospheric (in the air or weather)	blizzards, thunderstorms, lightning, tornadoes, tropical cyclones, drought, hailstorm, frost, heat wave (loo), cold wave
Terrestrial (on or under the land)	earthquakes, volcanic eruptions, landslides, avalanches, subsidence (the ground slowly sinking), soil erosion
Aquatic (in water)	floods, tidal waves, ocean currents, storm surge (sea water pushed onto land by a cyclone's winds), tsunami
Biological (living things)	plants and animals as colonisers (locusts etc.), insect infestation; fungal, bacterial and viral diseases such as bird flu and dengue

• Traps:
• Drought is atmospheric, not terrestrial. It starts with too little rain.
• Tsunami is aquatic, even though an undersea earthquake (terrestrial) usually causes it.
• Storm surge is aquatic, even though a cyclone (atmospheric) drives it.
• Loo is the hot, dry summer wind of north-west India. It counts as a heat wave.

10. Biological disasters in recent years

• Desert locust upsurge (2019-20): huge swarms entered from Pakistan and attacked crops in Rajasthan and Gujarat (and later other states). Locusts are a classic "coloniser": they breed fast in good conditions and eat any green crop in their path.
• COVID-19: in March 2020, it was notified as a disaster under the Disaster Management Act, 2005. This allowed national lockdown orders to be issued under that law. It shows that a pandemic counts as a biological disaster.

11. Legal frame: DM Act 2005 and its 2025 amendment

• The Disaster Management Act, 2005 created the NDMA (National Disaster Management Authority, chaired by the Prime Minister), SDMAs (state authorities) and DDMAs (district authorities).
• The Disaster Management (Amendment) Bill, 2024 was introduced in the Lok Sabha on 1 August 2024 [4] and became the DM (Amendment) Act, 2025. Key changes:
• National and state disaster databases, holding the type and severity of disaster risks, how funds are given and spent, and preparedness and mitigation plans [4][5].
• States may set up an Urban Disaster Management Authority for state capitals and cities with a municipal corporation. The Municipal Commissioner is chairperson and the District Collector is vice-chairperson [4][5].
• New NDMA functions: assessing states' disaster preparedness and doing a post-disaster audit of preparedness and response [4].

• NDMA gets power to make regulations under the Act, with the Centre's prior approval [4].

• The databases and audits put the risk idea into practice: they measure hazard, exposure and capacity, not just pay relief afterwards.

Prelims Hooks

• Hazard vs disaster: a hazard is a possible threat. It becomes a disaster only when its damage is large-scale and is beyond the community's own coping capacity.
• Drought is classed as an atmospheric disaster. Tsunami, storm surge and tidal waves are aquatic. Subsidence and soil erosion are terrestrial (NCERT Table 6.1).
• Bhopal gas tragedy: methyl isocyanate (MIC), Union Carbide pesticide plant, night of 2-3 December 1984, Madhya Pradesh. It led to the Environment (Protection) Act 1986 and the Public Liability Insurance Act 1991.
• Chernobyl, CFC release and wars are direct human-made disasters. Floods and landslides caused by deforestation are indirect ones.
• India's profile: about 58.6% of land is earthquake-prone, about 12% (40 million ha) is flood-prone, about 5,700 km of the 7,516 km coastline faces cyclones and tsunamis, and 68% of cultivable area is drought-prone [2].
• UNDRR: disaster risk is a function of hazard, exposure, vulnerability and capacity. The terminology was adopted by the UNGA on 2 February 2017 [3].
• Order of global frameworks: Yokohama (1994) → Hyogo (2005-2015) → Sendai (2015-2030).
• COVID-19 was notified as a disaster under the DM Act 2005 in March 2020. Biological disasters also include locusts, bird flu and dengue.
• DM (Amendment) Act, 2025: Urban DMA headed by the Municipal Commissioner, plus national and state disaster databases [4].

Mains Points

• Why disaster losses in India keep rising even when hazards do not grow (GS-I/III):
• Technology-led crowding into floodplains and coastal megacities (Mumbai, Chennai) raises exposure.
• Poverty, social discrimination and weak housing raise vulnerability.

• So policy must focus on reducing risk, not only on relief (Risk = H × E × V ÷ C).

• Human-made and indirect disasters:

• Deforestation, unscientific land use and building in fragile Himalayan and riverine areas turn natural hazards into disasters.
• Bhopal (1984) shows the industrial side: chemical units placed next to dense, poor settlements.

• Land-use zoning, environmental impact assessment and liability laws (EPA 1986, PLIA 1991) are the answers.

• India's multi-hazard profile needs region-specific plans:

• Earthquake-safe building codes for the Himalayas and North-East.
• Flood plain zoning for the Ganga–Brahmaputra plains.
• Cyclone shelters and early warning on the east coast.

• Drought-proofing for the 68% drought-prone cultivable area [2].

• Institutional shift from relief to risk reduction:

• Sendai Framework (2015-2030) goals are reflected in the DM (Amendment) Act 2025.
• Its tools are disaster databases, Urban Disaster Management Authorities, and NDMA audits of state preparedness [4][5].
• It also widens what counts as a disaster, e.g. COVID-19 (2020) and locust upsurges (2019-20).